Love our website? We do too. Did you know we're a charity? Donate now to help us keep it free for everyone in Aotearoa New Zealand.

Cows' milk allergy or lactose intolerance?

Key points about cows' milk allergy and lactose intolerance

Cows' milk allergy and lactose intolerance are often confused with each other.
While some of the gastrointestinal (gut) symptoms can appear similar, they are not the same thing.
This page provides information about how they are different.

Print this page

The following table is a summary of some of the differences between cows' milk allergy and lactose intolerance. For more details see cows' milk allergy and lactose intolerance.

If you think your baby has symptoms related to their infant formula, talk to your healthcare provider. Making the correct diagnosis is important so your baby can be given the most suitable formula and so, if needed, you can avoid giving them some foods.

Cows' milk allergy (CMA)	Lactose intolerance
Cause Happens when your baby's immune system reacts to proteins in cows' milk. There are 2 main types of CMA: IgE-mediated CMA Non-IgE-mediated CMA. Some babies may have a mixed allergic reaction.	Cause Occurs when your body doesn’t produce enough of the enzyme lactase, which breaks down lactose in your gut.
Ages affected Symptoms usually start during the first few months of life and generally get better before the age of 3 years.	Ages affected Usually seen over 6 years of age. Infants and young children can have temporary lactose intolerance, usually after a tummy infection (viral gastroenteritis). It can last for about 4 weeks before the gut recovers and starts to break down lactose again.
Symptoms Symptoms differ depending on the type of allergic reaction. IgE-mediated CMA symptoms usually involves skin (it turns red, itchy, has hives or swelling), tummy (such as vomiting, runny poos or tummy pain), breathing problems (such as runny nose, noisy breathing, cough or wheeze) or your baby gets pale and floppy. Non-IgE-mediated CMA symptoms usually involve tummy symptoms such as vomiting, runny poos or tummy pain and blood in the poos.	Symptoms Lactose intolerance only causes tummy symptoms, such as runny poos, tummy pain or bloating It doesn't cause blood in the poos.
Treatment Completely remove cows' milk, dairy products and any foods with cows' milk-containing ingredients from your baby's diet. If your infant is formula fed, it's important to choose the correct type of formula. There are 3 options for babies with CMA (the choice depends on your baby's age and the type of CMA they have): soy formula (not funded) extensively hydrolysed formula amino acid formula. Note: A lactose-free formula is not suitable for babies with CMA. Read more about infant formula for cows' milk allergy.	Treatment Infants with lactose intolerance need to minimise lactose in their diet rather than totally cut it out, as they are likely to tolerate small amounts of lactose. Lactose-free formulas are suitable. A soy infant formula can be used in babies older than 6 months. Read more about infant formula products.